Lawn-Boy
Gas Walk-Behind Mower

Model #S21ZPR Lawn-Boy lawn mower

Here are the diagrams and repair parts for Lawn-Boy S21ZPR lawn mower, as well as links to manuals and error code tables, if available.


There are a couple of ways to find the part or diagram you need:

  • Click a diagram to see the parts shown on that diagram.
  • In the search box below, enter all or part of the part number or the part’s name.

Not all parts are shown on the diagrams—those parts are labeled NI, for “not illustrated”.

We encourage you to save the model to your profile, so it’s easy to access parts and manuals for your appliance whenever you log in.

For DIY troubleshooting advice and repair guides, visit our repair help section.

Save to my profile

Showing 10 of 185 parts

Screw

#10

Housing and shroud group Diagram

Screw

Part #606733
?
Manufacturer substitution
This part replaces 606733. Substitute parts can look different from the original.
This part replaces 606733
This item is not returnable
$4.56

In Stock

Hex Washer Screw

#25

Engine group Diagram

Hex washer screw

Part #613110
?
Manufacturer substitution
This part replaces 613110. Substitute parts can look different from the original.
This part replaces 613110
$9.84

In Stock

Rod

#15

Housing and shroud group Diagram

Rod

Part #608174
?
Manufacturer substitution
This part replaces 608174. Substitute parts can look different from the original.
This part replaces 608174
$10.51

In Stock

Repair

#NI

All parts Diagram

Repair

Part #683777
?
Manufacturer substitution
This part replaces 683777. Substitute parts can look different from the original.
This part replaces 683777
$14.36

In Stock

Screw

#42

Engine group Diagram

Screw

Part #614343
?
Manufacturer substitution
This part replaces 307028. Substitute parts can look different from the original.
This part replaces 307028
This item is not returnable
$2.38

In Stock

Toe Bar

#35

Housing and shroud group Diagram

Toe bar

Part #608175
?
Manufacturer substitution
This part replaces 608175. Substitute parts can look different from the original.
This part replaces 608175
$39.50

In Stock

Screw

#44

Housing and shroud group Diagram

Screw

Part #612428
?
Manufacturer substitution
This part replaces 612428. Substitute parts can look different from the original.
This part replaces 612428
This item is not returnable
$2.33

In Stock

Nut

#16

Housing and shroud group Diagram

Nut

Part #608311

The manufacturer no longer makes this part, and there's no substitute part

Washer

#57

Engine group Diagram

Washer

Part #603093
?
Manufacturer substitution
This part replaces 603093. Substitute parts can look different from the original.
This part replaces 603093
This item is not returnable
$6.86

In Stock

Washer

#23

Housing and shroud group Diagram

Washer

Part #605255
?
Manufacturer substitution
This part replaces 605255. Substitute parts can look different from the original.
This part replaces 605255
This item is not returnable
$2.27

In Stock

Symptoms for gas walk-behind mowers

Choose a symptom to see related walk-behind mower repairs.

Main causes: drive control cable failure, worn or broken drive belt, bad transmission, broken drive wheel
Main causes: uneven wheel height settings, damaged wheel, dull or damaged cutting blade
Main causes: dirty carburetor, bad spark plug, clogged air filter, engine choke problems, clogged gas cap vent
Main causes: damaged cutting blade, loose cutting blade, damaged flywheel key, engine needs tune up
Main causes: engine needs tune up, dirty or clogged carburetor, damaged flywheel key
Main causes: stale gas, engine needs tune up, bad spark plug, dead battery, bad recoil starter, faulty safety switch, bad ignition coil

Repair guides for gas walk-behind mowers

These step-by-step repair guides will help you safely fix what’s broken on your walk-behind lawn mower.

How to replace a lawn mower flywheel key on an OHV engine

The flywheel key couples the flywheel to the engine crankshaft. Replace the flywheel key if it's broken.

Repair difficulty
Time required
 60 minutes or less
April 1, 2013
By Lyle Weischwill
How to replace a lawn mower wheel

Learn how replace a damaged wheel on a walk-behind lawn mower—it's a quick, easy fix.

Repair difficulty
Time required
 15 minutes or less
April 1, 2013
By Lyle Weischwill
How to replace a lawn mower safety switch

The safety switch stops the engine when you release the lever on the handle. This repair guide explains how to replace it if it's not working correctly.

Repair difficulty
Time required
 30 minutes or less

Articles and videos common to all walk-behind mowers

Use the advice and tips in these articles and videos to get the most out of your walk-behind lawn mower.

October 1, 2019

Types of walk-behind mower blades video

By Sears PartsDirect staff

Learn about the different kinds of mower blades and how to maintain them.